JP3122306B2 - Horizontal narrow groove gas shielded arc welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal narrow groove gas shielded arc welding method.

[0002]

2. Description of the Related Art Conventionally, in performing gas shielded arc welding of a horizontal narrow groove, an upper wall corner portion and a lower wall angle of a narrow groove in which poor fusion is particularly likely to occur using a substantially I-shaped narrow groove. In order to orient the wire to the part and to prevent the molten metal from dripping and to stack the beads almost evenly,
A welding method as shown in FIG. 5 has been developed. 4 (A) and 4 (B) show a method in which the weld metal 22 is distributed above and below the horizontal narrow groove 17 and welded. In FIG. 4 (A), the welding of the lower wall corner 17b of the horizontal narrow groove 17 is performed. In order to secure the welding, the welding torch 20 equipped with the shielding gas nozzle is tilted slightly downward and the first pass is welded by the wire 21, and in FIG. The second pass is welded to the wall corner 17a, and the two layers of the weld metal 22 are sequentially laminated in this manner.
FIGS. 5A and 5B show a method of laminating a horizontal narrow groove 17 with one layer and one pass of a weld metal 22 by using a welding torch 20 'using a bellows type double shield gas nozzle. The welding is performed along the oscillating locus 24 while oscillating linearly obliquely from upper right to lower left with respect to the welding progress direction 23.

In the method shown in FIG. 4, however, the angle of the wire 21 with respect to the upper and lower wall surfaces of the laterally narrow groove 17 becomes more difficult to obtain as the plate thickness increases, so that poor fusion occurs at the upper wall corner 17a and the lower wall corner 17b. The welding efficiency is poor in the vertical sorting method.
Also, in the horizontal narrow groove welding of a thick groove having a deep groove, it is indispensable for the welding quality to completely shield the arc atmosphere from the atmosphere. However, in this method, air or the like is mixed into the weld metal 22 due to poor shielding. There is a problem that welding defects such as blow holes easily occur. On the other hand, in the method shown in FIG. 5, since the molten metal 22 is likely to hang down under the influence of gravity, the amount of weld metal on the lower wall side is larger than that on the upper wall side. In addition, overlap welding defects tend to occur on the lower wall side. In addition, since the supply of the shielding gas is from the outer surface of the groove, and air or the like is easily mixed into the weld metal due to poor shielding as described above, there is a problem that satisfactory welding quality cannot be obtained.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been proposed in view of such circumstances, and it is possible to reliably direct an arc to a corner of a wall, obtain sufficient penetration, and prevent dripping of molten metal. It is an object of the present invention to provide a horizontal narrow groove gas shielded arc welding method that can prevent the occurrence of welding defects, obtain good welded joints without welding defects, improve the gas shielding effect, and greatly improve the welding efficiency.

[0005]

SUMMARY OF THE INVENTION In order to achieve the object, the present invention provides a gas shielded arc welding of a lateral narrow groove, in which a wire bent at the tip of a tip is formed into an arc shape in a direction opposite to a welding progress direction and moves downward. Are repeatedly oscillated at a rotational speed that is faster than when moving up, and when lowering, welding is performed with a higher welding current and voltage than when moving up.

[0006]

In the horizontal narrow groove gas shielded arc welding method according to the present invention, welding is performed while rotating in the horizontal narrow groove in an arc shape in the direction opposite to the welding traveling direction, faster during downward movement than during upward movement. This allows the arc point to reach the corner of the lower wall before the molten metal flowing down due to gravity, and the heat of the arc can be supplied directly to the base material, increasing the heat input to the base material in this part, making it stable and satisfactory A good penetration. In the case where welding is performed by stopping at the time of reversal, the molten metal can be shaken off by accelerating just before the stop to further enhance this effect. In addition, the amount of heat input at the corner of the lower wall is increased by increasing the welding current and the voltage during the downward movement as compared with during the upward movement, thereby increasing penetration. Further, the moving distance traversing the narrow groove becomes longer in the case of the arc-shaped oscillate than the linear oscillate, and the above-described effect is further increased by increasing the stroke of the flow of the molten metal,
A weld bead with deep penetration, smooth surface and beautiful appearance can be obtained.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing an oscillating locus of the present welding method, and FIG. 2 is a diagram showing an oscillating procedure of the present welding method. FIG. 3 is a perspective view of a welding torch applied to the present welding method. First, a welding torch applied to the present welding method will be described with reference to FIG. 3. A tip rotating shaft 3 is vertically installed inside a flat shield nozzle 2 provided at a tip of a welding torch main body 1, and a tip of a coaxial 3 is provided. The chip 4 is screwed, and the chip 4 is provided with a wire lead-out hole 5 which is bent by 5 to 20 ° with respect to the axial direction, and a wire 6 is led out from the tip thereof. The base end of the tip rotating shaft 3 is connected to a stepping motor 9 capable of detecting an oscillating position and controlling a speed via a pair of gears 7 and 8 disposed through the welding torch main body 1 and disposed at the base of the main body 1. ing. Further, a plurality of shield gas supply pipes 10 are disposed in the shield nozzle 2 so that the shield gas inlet 1 is provided.
1 and a plurality of water supply pipes 12 and drain pipes 1
3 is connected to a cooling water inlet 14 and a cooling water outlet 15. The shield nozzle 2 can be fitted at its base with a double shield nozzle for ejecting a shield gas to the outer surface.

[0010] Referring to FIGS. 1 and 2, a description will be given of an embodiment of a welding method for performing a horizontal narrow groove gas shield arc welding using such a welding torch. First, in FIG. 2, a shield nozzle is provided in a horizontal narrow groove 17. 2 is inserted sideways in the wide direction, an arc is generated between the wire 6 bent and projected from the wire lead-out hole 5 at the tip of the tip 4 and the lateral narrow groove 17, and the shield gas is discharged from the shield nozzle 2. Welding is performed while the shield nozzle 2 is ejected and moved in the welding progress direction. At this time, by rotating the stepping motor 9 shown in FIG. 3, the tip rotating shaft 3 is rotated through the gear pairs 7 and 8, and as shown in FIG. The oscillation is repeated up and down in an arc shape in the direction opposite to the direction 18 like an oscillation locus 19. The oscillating trajectory 19 repeatedly turns at the upper wall corner 17a and the lower wall corner 17b and proceeds along the welding traveling direction 18.

By the oscillating operation based on the oscillating locus 19, the tip of the wire 6 changes to the position 6 'as shown in FIG. 2, and the maximum amplitude is obtained when the turning angle of the tip 4 is 180 °. As the angle decreases, the amplitude decreases in proportion to the amplitude of the wire 6. In this manner, the wire lead-out hole 5 bent by 5 to 20 ° with respect to the axial direction of the chip 4
The tip of the wire 6 derived from is repeatedly oscillated in an arc shape in the direction opposite to the welding progress direction by the rotation of the tip 4, thereby forming the upper wall corner 17 a and the lower wall corner 17 b of the lateral narrow groove 17. In this way, the arc can be reliably directed. In the course of this repetitive oscillating process, welding in a direction against gravity can cause penetration because the molten metal flows below the arc point and the heat of the arc can be directly applied to the base metal. In the welding in the direction, the molten metal is in the way and the heat of the arc does not directly hit the base metal, causing a phenomenon that the penetration is small. 1 (A)
19b), by making the arc point faster than when moving upward (19a), the arc point can be set earlier than the molten metal by the lower wall corner 1
Penetration can be ensured by reaching 7b. By increasing the welding current and voltage during the downward movement as compared with the upward movement, the amount of heat input to the lower wall corner 17b can be increased, and the amount of penetration can be increased. Furthermore, when the repetitive oscillating is performed, the upper wall corner 17a and the lower wall corner 17b are temporarily stopped at the time of reversal. When the upper and lower wall corners 17a and 17b are temporarily stopped, different upper and lower stop times are provided, and the rotation speed is accelerated immediately before the stop. The amount can be improved.

Next, a specific example of the method of the present invention will be described. For a low alloy steel having a thickness of 100 mm and a narrow I-shaped groove having a groove width of 16 mm, a wire diameter of 1.2 mm, a wire lead hole diameter of 1.5 mm, and a wire lead hole are provided. Angle 18 °, shielding gas Ar 80% + CO ₂ 20
%, Welding current: 300 to 350 A for downward movement, 170 to 200 A for upward movement, welding voltage: 25 to 30 for downward movement
V, 19-20V when ascending, welding speed: 11-13cm / mi
n, wire rotation speed: 600 to 700 DEG / se when moving down
c, Welding at 150-200 DEG / sec at ascent, stop time: 0.1-0.3 sec at lower end, 1.5-2.5 sec at upper end, rotation speed 1400-1600 DEG / sec immediately before stop,
Stable and favorable penetration of about 2 mm on each side in the groove wall direction and the plate thickness direction was obtained at the upper wall corner and the lower wall corner.

Thus, according to the horizontal narrow groove gas shielded arc welding, the arc-shaped oscillate at the tip of the wire 6 is repeatedly rotated in the direction opposite to the welding advancing direction 18, and the rotating speed is increased when moving downward. When moving upward, the rotation speed is reduced, so that stable and satisfactory penetration can be obtained without being hindered by the molten metal and dripping of the molten metal can be prevented. In addition, since the wire 6 can be accurately guided to the tip of the tip 4 via the tip rotating shaft 3, the wire 6 is surely directed to the upper wall corner 17a and the lower wall corner 17b, which are liable to cause defective fusion. This makes it possible to adjust the target position of the arc and the stopping time at both ends of the groove independently and in real time. Further, a flat shield nozzle 2 that can be inserted into the lateral narrow groove 17.
The effect of the gas shield in the lamination from the groove bottom portion to the finish layer on the groove surface can be improved by using.

[0012]

In summary, according to the present invention, in gas shielded arc welding of a laterally narrow groove, the wire bent at the tip of the tip is moved in an arc shape in the direction opposite to the welding progress direction and ascends when descending. Repetitive oscillating at a faster rotation speed than before, and further increasing the welding current and voltage compared to when ascending, and performing welding to ensure that the arc can be directed to the corners of the wall and sufficient penetration A horizontal narrow groove gas shielded arc welding method that can prevent dripping of the molten metal and obtain good welded joints without weld defects, and can improve the gas shielding effect and greatly improve the welding efficiency Therefore, the present invention is extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an oscillating trajectory in one embodiment of a horizontal narrow groove gas shielded arc welding method according to the present invention.

FIG. 2 is an explanatory diagram showing an oscillating procedure of the present welding method.

FIG. 3 is a perspective view of a welding torch applied to the present welding method.

FIG. 4 is an explanatory view of a conventional horizontal narrow groove gas shielded arc welding method.

FIG. 5 is an explanatory view of another conventional horizontal narrow groove gas shielded arc welding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding torch main body 2 Shield nozzle 3 Tip rotation axis 4 Tip 5 Wire lead-out hole 6 Wire 7,8 Gear 9 Stepping motor 10 Shield gas supply pipe 11 Shield gas inlet 12 Water supply pipe 13 Drain pipe 14 Cooling water inlet 15 Cooling water outlet 17 Horizontal narrow groove 17a Upper wall corner 17b Lower wall corner 18 Welding direction 19 Oscillate trajectory 19a Upward traveling 19b Downward traveling

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shiro Iijima 1-1, Akunouramachi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (72) Inventor Takayuki Kono 5-717-1, Fukahoricho, Nagasaki-shi Mitsubishi Heavy Industries (72) Inventor Hironobu Inoue 5-717-1 Fukabori-cho, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Research Institute (72) Inventor Osamu Shida 4-4-26-Setogoshi, Sasebo, Nagasaki Prefecture Shares (56) References JP-A-49-114546 (JP, A) JP-A-50-98454 (JP, A) JP-A-51-65052 (JP, A) JP-A-51-37851 (JP, A) A) JP-A-61-49776 (JP, A) JP-A-52-10841 (JP, A) JP-B-53-10936 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) B23K 9/173 B23K 9/022 B23K 9/095 B23K 9/12

Claims (2)

(57) [Claims] In a gas shielded arc welding of a lateral narrow groove, a wire bent at a tip of a tip is formed into an arc shape in a direction opposite to a welding progress direction, and a rotation speed when moving down is faster than when moving up. A horizontal narrow groove gas shielded arc welding method characterized in that the welding is repeated at a lower speed and the welding current and voltage are made higher than during the upward movement. 2. A horizontal narrow groove gas shielded arc welding as claimed in claim 1, wherein different up and down stop times are provided in the course of repetitive oscillating of the wire, and the turning speed is accelerated immediately before the stop. Method.